Cradle for connecting to portable electronic apparatus

ABSTRACT

A cradle for connecting to a portable electronic apparatus is described. The cradle includes an AC adapter connector, a USB connector, a mini USB plug, and a USB signal detecting circuit. The USB connector is used to connect to a USB interface of a computer. The mini USB plug is used to connect to the portable electronic apparatus. The USB signal detecting circuit detects the USB_D+ and the USB_D− of the USB connector. When the computer is suspended from an operating state, the portable electronic apparatus is charged by the AC adapter through the mini USB plug. When the computer resumes normal operation, the USB connection between the portable electronic apparatus and the computer is automatically reestablished.

RELATED APPLICATIONS

The present application is based on, and claims priority from, TaiwanApplication Serial Number 94121962, filed Jun. 29, 2005, the disclosureof which is hereby incorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION

1. Field of Invention

The invention relates to a cradle for connecting to a portableelectronic apparatus and, in particular, to a cradle that automaticallyswitches between the USB connection and the AC adapter.

2. Related Art

In the past, portable electronic devices, such as the handheldmultimedia mobile devices like PDAs, PDA phones, smart phones, mobilephones, MP3 players, Portable Media Players (PMP), Digital Videos (DV)and Digital Cameras (DC), can be connected to a computer to establish aUSB connection. They can also use an AC adapter to charge theirbatteries. More and more devices are being configured with a mini USB asthe I/O interface as the devices are designed increasingly smaller andlighter weight. PDAs especially exemplify this trend.

When establishing a USB connection using the mini USB, a PDA is notcharged by the AC adapter. When using the USB to charge via the ACadapter, the PDA interrupts the USB connection to the computer. It isthen necessary to manually reestablish the connection. The USBconnection to the computer is also interrupted and remains broken whenthe computer suspends from its operating state. When the computerresumes operation, the PDA does not automatically reconnect to thecomputer using the USB port. Therefore, the conventional PDA cradle hasmany disadvantages.

Therefore, a new cradle for solving the above-mentioned inconvenience isnecessary and very important to the field.

SUMMARY OF THE INVENTION

An object of the invention is to provide a cradle for connecting to aportable electronic apparatus, such that the cradle uses a single miniUSB connector to switch between the charge mode and the USB connectionmode.

Another object of the invention is to provide a cradle for connecting toa portable electronic apparatus, such that the cradle can automaticallydetect a USB connection or transformer charging.

Yet another object of the invention is to provide a cradle forconnecting to a portable electronic apparatus, such that the computercan automatically reestablish the connection without having tophysically reconnect the USB wire when the computer is restored fromsuspension.

In accord with the above objects, the invention provides a cradle forconnecting to a portable electronic apparatus. According to a preferredembodiment of the invention, the cradle includes an AC adapterconnector, a USB connector, a mini USB plug, and a USB signal detectingcircuit.

The adapter connector is used to connect to an AC adapter. The USBconnector has a USB_D+ and a USB_D− contact. The USB connector is usedto connect to a computer USB interface. The mini USB plug is used toconnect to a portable electronic apparatus.

The USB signal detecting signal detects the USB_D+ and USB_D− contact ofthe USB connector. When the computer is suspended from an operatingstate, the portable electronic apparatus is charged via the mini USBplug by the AC adapter. When the computer resumes its operating state,the portable electronic apparatus automatically reestablishes the USBconnection with the computer.

The invention has at least the following advantages, wherein eachembodiment has one or more advantages. The disclosed cradle can use asingle mini USB connector to switch between a charge mode and a USBconnection mode. The disclosed cradle can automatically detect a USBconnection or transformer charging. And, the disclosed cradle canautomatically reestablish the connection once the computer resumes itsoperating state without having to physically reconnect the USB wire.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will become more fully understood from the followingdetailed description taken in conjunction with the accompanyingdrawings, which serve to illustrate and not limit the invention,wherein:

FIG. 1 is a block diagram of an embodiment of the invention; and

FIG. 2 is a flowchart showing the operation of the disclosed cradle.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be apparent from the following detaileddescription, which proceeds with reference to the accompanying drawings,wherein the same references relate to the same elements.

With reference to FIG. 1, the disclosed cradle 102 is used to connect toa portable electronic apparatus 120. Via the cradle 102, the portableelectronic apparatus 120 can be charged or connected to a computer 118via its USB interface 124.

The cradle 102 has a USB connector 104, an AC adapter connector 108, anda mini USB plug 106. The USB connector 104 is connected to the USBinterface 124 of the computer 118. The AC adapter connector 108 isconnected to an AC adapter 122. The mini USB plug 106 is connected to aportable electronic apparatus 120.

When only the computer 118 is connected to the cradle 102, the cradle102 establishes a USB connection via the USB connector 104 and the miniUSB plug 106. The computer 118 can thus exchange data with the portableelectronic apparatus 120.

When only the AC adapter 122 is connected to the cradle 102, theportable electronic apparatus 120 is charged via the cradle 102. Theportable electronic apparatus 120 is charged via USB_VBUS of the miniUSB plug.

When the computer 118 is connected to the cradle 102 and the AC adapter122 is also connected to the cradle 102, the cradle 102 determineswhether to establish a USB connection or to charge, depending upon thesituation. When the computer 118 is in an operating state, the cradle102 has a higher priority to establish the USB connection. Therefore,the computer 118 and the portable electronic apparatus 120 are in theUSB connection state. In other words, the priority of the USB connectionis higher than the connection to the AC adapter 122. When the computer118 is suspended, the cradle 102 allows the portable electronicapparatus 120 to be charged via the AC adapter 122. The charging isperformed by the AC adapter 122 via the AC adapter connector 108 and theUSB_VBUS of the mini USB plug 106.

Of course, when the portable electronic apparatus 120 and the computer118 are in the USB connection state, USB_VBUS of the USB connector 104and USB_VBUS of the mini USB plug 106 are connected together, whichallows a small charging current. This charging current through thecomputer 118 is smaller (about 500 mA) than the charging current via theAC adapter 122 (the maximum charging current provided by the ACadapter).

FIG. 2 depicts the flowchart of operating the disclosed cradle. Withsimultaneous reference to FIGS. 1 and 2, when the cradle 102 is neitherconnected to the computer 118 nor to the AC adapter 122, the settingsPWR_IN=1 and USB_ID=1 (step 202). PWR_IN=1 means that both USB_VBUS ofthe USB connector 104 and the AC power source do not have any powersignal input.

Afterwards, a power input signal detecting circuit 110 detects whetherthere is any power input (usually 5V) at USB_VBUS of the USB connectorand whether there is any power input at the AC adapter connector 108(step 204). If the AC adapter connector 108 receives a power input andthe USB connector 104 does not receive any power input, the settingsPWR_IN=0 and USB_ID=0 (step 208). At this moment, the cradle 102 entersthe AC adapter charging mode. The maximum charging current provided bythe AC adapter is used to charge the portable electronic apparatus 120via USB_VBUS of the mini USB plug 106 (step 218). When the AC adapter122 is removed, the cradle 102 returns to the settings PWR_IN=1 andUSB_ID=1 (step 202).

If the USB connector 104 receives a power input, the settings becomePWR_IN=0 and USB_ID=1 (step 206). At this moment, the portableelectronic apparatus 120 and the computer 118 establish a connection viaa USB cable. The cradle 102 is connected to USB_VBUS of the mini USBplug 106 via USB_VBUS of the USB connector 104 to charge the portableelectronic apparatus 120. The current is about 500 mA (step 210).

If the USB connector 104 receives a power input and the AC adapter 122is connected to the AC adapter connector 108, the settings are PWR_IN=0and USB_ID=1 (step 206). In this case, the USB connection isestablished. The cradle 102 is connected to USB_VBUS of the mini USBplug 106 via USB_VBUS of the USB connector 104 to charge the portableelectronic apparatus 120. The current is about 500 mA (step 210).

Afterwards, a USB signal detecting circuit 112 detects whether thecomputer is in an operating state or suspended state (step 212). Whenthe timing on USB_D+ and USB_D− contact of the USB connector 104 has aspecific variation (e.g. the period during which it is not maintained ata specific potential level is greater than 300 ms), then the USB signaldetecting circuit 112 determines that the computer 118 is in anoperating state and keeps the original USB connection.

When the timing on USB_D+ and USB_D− contact of the USB connector 104does not have a specific variation (e.g. the period during which it ismaintained at a specific potential level is greater than 300 ms), thenthe USB signal detecting circuit 112 determines that the computer 118 isin a suspended state. The settings of the cradle 102 are then PWR_IN=0and USB_ID=0 (step 214). At this moment, the cradle 102 disconnects theswitch 114 and uses the switch 116 to pull high USB_D+ of the USBconnector 104, so that USB_D+ of the USB connector 104 is maintained ata predetermined high voltage. Although the settings are PWR_IN=0 andUSB_ID=0, the computer 118 still considers the portable electronicapparatus 120 to be in a USB connected state for the convenience ofrestoring the USB connection in the future.

In step 214, the computer 118 still considers the portable electronicapparatus 120 to be in the USB connected state. However, the AC adapter122 charges the portable electronic apparatus via USB_VBUS of the miniUSB plug 106. In this case, the charging current can reach the maximumprovided by the AC adapter.

Afterwards, the USB signal detecting circuit 112 continues detecting thetiming on USB_D+ and USB_D− contact of the USB connector 104 todetermine if there is any specific variation (e.g. it is maintained at aspecific potential level). If the timing has any variation, the USBsignal detecting circuit 112 considers the computer 118 as back to itsoperating state. The cradle 102 has the settings PWR_IN=0 and USB_ID=1.Moreover, the switch 114 resumes its connection, while the switch 116 isdisconnected. Thus, USB_D+ of the USB connector 104 and USB_D− of themini USB plug 106 are connected to resume the USB connection (step 216).At the same time, the 500 mA charging on USB_VBUS is also resumed (step210).

If the timing on USB_D+ and USB_D− contact of the USB connector 104 hasa continuous variation, then step 214 continues for the AC adapter 122to charge the portable electronic apparatus 120. The above-mentionedportable electronic apparatus 120 may be a multimedia portable apparatussuch as a PDA, PDA phone, smart phone, mobile phone, MP3 player,Portable Media Player (PMP), Digital Video (DV), and Digital Camera(DC).

The invention has at least the following advantages, wherein eachembodiment features one or more of them. The disclosed cradle uses asingle mini USB plug to switch between a charge mode and a USBconnection mode. The disclosed cradle can automatically detect the USBconnection or transformer charging. When the computer resumes operationfrom being suspended, the disclosed cradle can automatically reestablishthe connection without having to physically reconnect the USB cable.

Certain variations would be apparent to those skilled in the art,variations which are considered within the spirit and scope of thefollowing claims.

1. A cradle for connecting to a portable electronic apparatus,comprising: an AC adapter connector used to connect to an AC adapter; aUSB connector having a USB_D+ and a USB_D− contact for connecting to aUSB interface of a computer; a mini USB plug used to connect to theportable electronic apparatus; a USB signal detecting circuit, whichdetects the USB_D+ and the USB_D− contact of the USB connector todetermine whether the computer is in an operating state where timing onthe USB_D+ and the USB_D− contact of the USB connector has a specificvariation or a suspended state where timing on the USB_D+ and the USB_D−contact of the USB connector has no specific variation; and a switchcoupled between the USB D+ contact of the USB connector and a USB D+contact of the mini USB plug, so that when the computer is suspended,the switch disconnects and the USB D+ contact of the USB connector ismaintained at a high potential level via another switch; wherein whenthe computer is suspended from the operating state, the portableelectronic apparatus is charged directly by the AC adapter via the miniUSB plug and the AC adapter connector and establishes no USB connectionwith the computer, and when the computer resumes its operating statefrom the suspended state, the portable electronic apparatusautomatically reestablishes the USB connection with the computer withouthaving to physically reconnect the USB connector.
 2. The cradle of claim1, further comprising: a power input signal detecting circuit fordetecting a USB_VBUS of the USB connector and detecting an input powerof the AC adapter, wherein the USB signal detecting circuit detectswhether the computer is in its operating state when the USB_VBUS and theinput power of the AC adapter exist concurrently.
 3. The cradle of claim1, wherein the USB signal detecting circuit determines that the computerin one of the operating state and a suspended state by a variation oftiming on the USB_D+ and the USB_D− contact of the USB connector.
 4. Thecradle of claim 1, wherein the cradle uses a detection result of the USBsignal detecting circuit to determine a USB_ID value of the mini USBplug.
 5. The cradle of claim 1, wherein the portable electronicapparatus is a portable apparatus selected from the group consisting ofa PDA, a PDA phone, a smart phone, a mobile phone, an MP3 player, aPortable Media Player (PMP), a Digital Video (DV), and a Digital Camera(DC).
 6. A method for switching a connection state of a portableelectronic apparatus, comprising: receiving a USB signal by a computervia a USB interface; detecting a USB_D+ and a USB_D− of the USB signalto determine whether the computer is suspended from an operating statewhere timing on the USB_D+ and the USB_D− contact of the USB connectorhas a specific variation; charging the portable electronic apparatus viaa mini USB interface directly by an AC adapter without establishing USBconnection with the computer when the computer is in a suspended statewhere timing on the USB_D+ and the USB_D− contact of the USB connectorhas no specific variation; automatically reestablishing a USB connectionbetween the portable electronic apparatus and the computer when thecomputer restores its operating state from being suspended, wherein theUSB connection is via the mini USB interface; using a switch todisconnect the connection between the USB D+ of the USB interface andthe USB D+ of the mini USB interface; and using another switch tomaintain a high voltage on the USB D+ of the USB interface.
 7. Themethod of claim 6, further comprising: detecting a USB-VBUS of the USBinterface and detecting an input power of the AC adapter; and detectingwhether the computer is in an operating state when the USB_VBUS and theinput power of the AC adapter exist concurrently.
 8. The method of claim6, further comprising: determining that the computer is in one of theoperating state and a suspended state by setting a USB_ID value of themini USB interface.
 9. The method of claim 6, further comprising: usingthe USB_D+ and the USB_D− of the USB signal to determine a USB_ID valueof the USB interface.
 10. The method of claim 6, wherein the portableelectronic apparatus is a portable apparatus selected from the groupconsisting of a PDA, a PDA phone, a smart phone, a mobile phone, an MP3player, a Portable Media Player (PMP), a Digital Video (DV), and aDigital Camera (DC).